July 30, 2026

The “immortal jellyfish,” Turritopsis dohrnii, has an extraordinary survival ability. When it’s injured, starving, or under severe stress, it can reverse its life cycle.

Instead of dying, it transforms its adult body back into a juvenile polyp, the stage it was in before becoming an adult. From there, it can grow into an adult all over again.

A few fascinating details:

It’s the only known animal that can repeatedly revert from adulthood to an earlier life stage.
This doesn’t mean it can’t die—it can still be eaten by predators, succumb to disease, or be destroyed by environmental conditions.
Scientists study it in hopes of learning more about cell regeneration and the biology of aging.

It’s one of the closest things in nature to hitting a biological “reset” button.